The invention relates to (bio)chemical reagent solid phases which are comprised of a polymer or macromolecular NH2-containing support compound, on which coupling structures are bound via NH2 groups covalently and which is further coupled with a receptor compound and/or indicator compound and thus the receptor and/indicator compounds can be coupled to the carrier. The invention also relates to a process for producing (bio)chemical reagent solid phases and their applications.
With (bio)chemical reagent solid phases of the aforedescribed type, by the coupling of receptor compounds to the carrier compound, the receptors can be immobilized. Such immobilized receptor compounds have utility in a variety of fields and have been known for a long time. A typical field of use is in biotechnology, in (bio)chemical sensors and biochemical analysis as, for example, chromatography. Of interest are special immobilized biological compounds like enzymes or immunoproteins. With these, the (enzyme) catalytic function or complementarity is used for producing and/or purifying substances or by complementarity is used analytically for detection of analyte materials and for signal processes.
With respect to the immobilization process and the composition of reagent solid phases, there is an enormous variation described in the technical literature. They are produced above all by the modification:
of the structure of the carrier compound as, for example,
macromolecular carriers of an organic or inorganic nature like collagens, dextrans or porous glass and the like and
polymeric carriers of polar and nonpolar nature like polyamides, polyurethanes or polystyrenes, polyethylenes or the like;
of an immobilizing kind or utilizing an immobilization process as for example
immersion or adsorption
electrostatic or covalent fixation, for example, via so-called bifunctional coupling compounds typically by means of glutaricdialdehyde or the like or
via the use of conventional synthesis reaction, e.g. substitution reactions, diazotizing reactions or the like;
of the receptor compound, for example,
biocompounds like enzymes (oxide reductases, proteases or the like or immunoproteins (antibodies) or
organic receptor compounds like crown ethers for ions or the like.
See Hermanson, G. T. et al (Ed.): Immobilized Affinity Ligand Technics, Academic Press, 1992 or Chibatu, I. (Ed.): Immobilized Enzymes, Research and Development, Kodanska Scientific Books, 1978).
Especially for the immobilization of biocompounds like enzymes or immunoproteins, polysaccharides, especially cellulose can be used as the carrier compound. For all of the important immobilization categories like
carrier inclusion,
ion association
covalent bonding
a multiplicity of variations have been found also with respect to the biocompounds which are incorporated. Table 1, assembles a collection of selected possibilities (compare the above-cited Hermanson, G. T. et al).
The columns in Table 1 can be expanded with respect to further cellulose derivatives, for example, cellulose carbonate chloracetylcellulose, bromacetylcellulose, etc., and also with reference to further biocompounds, for example, further enzyme species, NAD- and pyridoxal-phosphate coenzyme, vitamin B12, immunoproteins and the like.
In the forefront of the examples given, are preparative or analytic, e.g. chromatographic, applications in which the carrier compounds with receptor compounds or enzymes will depend only on the loading density and without special molecular geometric considerations.
With respect to the functional requirements, for example with the enzyme immobilization process, very different scales apply depending upon the field of use. Target criteria of an effective enzyme immobilization are
a precise folding of the proteins,
a free substrate accessibility of the active center,
an effective product recovery,
carrier fixation on the enzyme-molecular periphery,
a high enzyme loading density per unit of carrier matrix surface and
in the case of use as a sensor, a carrier matrix with signal structure features which affords a maximum optical or electronic transfer signal transduction.
The use of reagent solid phases in (bio) chemical sensor technology requires that, for each sensor development for a respective analyte, a new structure optimization based upon the aforestated criteria; the sensor solution for one analyte then can hardly be used for other analytes without further translation. This drawback in the state of development in the (bio) chemical sensor field makes the use of many scientifically determined sensor developments limited in practice, because there is a significant gap between the requirements of the sensor user and the generally limited functional stability and cross sensitivity of the sensors.
A solution of this problem was expected from sensor transducers of a xe2x80x9cmeasurement-tailoredxe2x80x9d supermolecular structure with improved signal transmission characteristics. Such a transducer is known, for example, from enzyme electrode developments, using polymeric carrier compounds with so-called electron mediator structures, e.g. ferrocene derivatives, and immobilized enzymes, for improved signal transduction by reduction of the electron transition xe2x80x9cbarriersxe2x80x9d, and the measurement electrode (see B. Frew, J. E. and Hill, H. A. O. (1987); Electrochemical Biosensors, Anal. Chem. 59, 933A; Frew, J. E. and Hill, H. A. O. (1987): Electron-transfer-Biosensors, Phil. Trans. R. Soc. B316, 95; Bockris, J. O""M. and Khan, S. U. M. (Ed.): Surface Electro-chemistryxe2x80x94A Molecular Level Approach, Plenum Press, 1993).
Significantly more complex supermolecular structures are required in the case of (bio) chemical glass fiber sensor transducers. The higher complexity is based upon the fact that an enzyme protein which possesses the requisite function and in most cases in addition, a further structure component, for example, an indicator structure, must be provided in a well-defined molecularly geometric positioning of the structures relative to one another on the polymer or macromolecular carrier matrix. Exceptions in which an additional signal structure is not required form analyte recognition structures wherein the analyte recognition and the optical signal transfer are inherent in the structure; for these up to now there have however been few examples.
In the field of glass fiber sensor technology there have already been reagent solid phases used which have cellulose derivatives as carrier compounds, on which pH indicators have been immobilized via vinyl sulfonyl groups as couplers (Weigl, B. H. et al. (1993): Robust Carbon Dioxidoptrode Based on a Covalently Immobilized pH-Indicator, SPIE-Vol. 2068, 2). In addition, the use of cellulose acetate membranes in combination with pH indicators has been described (Sansubrino, A. and Mascini, M. (1994): Development of an Optical Fiber Sensor for Ammonia, Urea, Urease and IgG, Biosens. Bioelectron. 9, 207).
The development of (bio) chemical glass fiber sensors is of special interest because of their capacity for integration, the possibility of a high degree of miniaturization and further advantageous characteristics, they are well characterized for use in analytic micro systems, for example, in vivo diagnostics in medicine. A substantial prerequisite which, up to now has been deficient, has been sensor transducers with improved signal transmission characteristics on the basis of corresponding xe2x80x9cmeasurement tailoredxe2x80x9d supermolecular structures which can be fabricated from readily accessible and least expensive starting materials, using the simplest possible process.
It is an object of the invention to prepare new (bio) chemical reagent solid phases whose structure allows the widest possible range of modification possibilities and thus a high degree of versatility, especially as analyte sensitive solid phases in sensor technology. It is also an object of the invention to provide a simple process for producing such reagent solid phases.
These objects are attained in accordance with the invention with a polymeric macromolecular, NH2-containing carrier compound with coupling structures covalently bonded via NH2 groups, whereby the coupling structures are comprised of ascorbic acid or dehydroascorbic acid or a compound structurally similar to one of these substances. The coupling structures are, moreover, linked with a receptor compound and/or indicator compound so that these are coupled to or immobilized on the carrier. As substances structurally similar to ascorbic acid or dehydroascorbic acid, mention may be made especially of L-2,3-diketogulonic acid or a derivative thereof. There are compounds which can be included as structurally similar compounds which include for example compounds with at least two keto groups, like acetylacetone.
An alternative solution according to the invention for the aforementioned objects are (bio) chemical reagent solid phases of the described type in which the carrier compound is a cellulose derivative of the following formula I: 
in which
R1. R2 =H
or R1=H, R2=substituent with a degree of substitution xe2x89xa61
or R1 is a substituent of degree of substitution xe2x89xa61, R2=H
or R1, R2=a substituent with a degree of substitution xe2x89xa62
and R3 is an aromatic substituent which contains at least one free amino group and a degree of substitution xe2x89xa61.
The residue R3 is preferably an amino residue of the formula 
X=H or H and/or substituents
As the amine or amine residue, compounds can be used for example with the following structural formulas: 
X=H or H and/or substituents
Y=H or H and/or substituents
According to the formula I, the basic framework is either cellulose (R1, R2=H) or a cellulose derivative. In case, a cellulose derivative basic framework is provided, the substituent in the R1 position and/or R2 position, is an alkyl, preferably CH3, or acyl, preferably acetyl, or a tosyl residue or a tresyl residue. The substituent in the named position can be exclusively a substituent of the named type or in the R1 position and/or R2 position can be within a macromolecule which can include different substituents of the named type.
The (bio) chemical reagent solid phase containing such a carrier compound can be used especially as the analyte sensitive solid phase in the sensor technology for which it is highly suitable since the carrier compounds have, above all, redox-chromogenic characteristics which, by multiple structural alterations by known coupling reactions to the free aromatic NH2 groups, provide a wide range of chromogenic modification possibilities. Because of the characteristics, supermolecular structures can be formed which signal the xe2x80x9crecognitionxe2x80x9d of the analyte (i.e. when the compound having an affinity to the receptor enters into an exchange therewith) which is optically xe2x80x9csignalledxe2x80x9d or xe2x80x9csignalsxe2x80x9d by electron transfer.
The supermolecular xe2x80x9cbasicxe2x80x9d structure according to the invention enables the following broadening or modification possibilities.